Stirling engine



FIG. 1 is a front, top perspective view of the stirling engine showing my new design;

FIG. 2 is a rear, top perspective view thereof;

FIG. 3 is a front, bottom perspective view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a left side elevational view thereof;

FIG. 7 is a right side elevational view thereof;

FIG. 8 is a top plan view thereof; and,

FIG. 9 is a bottom plan view thereof. 

CLAIM The ornamental design for a stirling engine, as shown and described. 